Josef Newgarden and Alexander Rossi are content following the second day of practice for the 103rd Indianapolis 500 presented by Gainbridge. Fernando Alonso, Felix Rosenqvist and their respective crews have work to do after separate incidents Tuesday at Indianapolis Motor Speedway.

Newgarden, the NTT IndyCar Series points leader after five of 17 races, ran the fastest of more than 3,200 laps turned by 36 drivers on the famed 2.5-mile oval Tuesday, at 228.856 mph in the No. 2 Shell V-Power Nitro Plus Team Penske Chevrolet.

"I think we need to be a bit better in traffic," said Newgarden, the 2017 series champion. "Still trying to figure out exactly what we need on the race car, that was kind of our focus today. We didn't really do much qualifying sims or anything like that.

"I think the Shell car feels OK. It's not a bad start. I'm trying to stay careful with it. I always try and respect this place at the beginning. I never try and push until it's time."

Scott Dixon, last year's series champion who trails Newgarden by six points heading into the Indy 500 on May 26, was second on the speed chart at 228.835 mph in the No. 9 PNC Bank Chip Ganassi Racing Honda.

Rossi logged the best lap without the tow of a leading car, at 224.648 mph in the No. 27 NAPA AUTO PARTS Honda for Andretti Autosport. The 2016 Indianapolis 500 winner said the speed was "irrelevant" this early in the week, but he was pleased his team worked through its practice checklist efficiently enough that he was able to sit out the closing hours of the afternoon.

"It was a good day," Rossi said. "Any day out here is a good day, for sure. Just running through a checklist of things to try and understand everything that we learned over the offseason and applying it to kind of all five (Andretti Autosport) cars in different ways and compiling as much information as we can.

"That's the advantage about being on a big team for this event. When you have this much practice, you can really kind of divide and conquer, and I think we're doing that well so far."

At the other end of the spectrum, Alonso and Rosenqvist were uninjured but had their days end abruptly in single-car crashes. Alonso's No. 66 McLaren Racing Chevrolet made contact with the Turn 3 SAFER Barrier some 95 minutes into the seven-hour practice. His car slid into the inside barrier on the short chute and then up the track to the outside barrier in Turn 4 before coming to rest.

Alonso exited the car without assistance but disappointed. The McLaren crew spent the afternoon preparing Alonso's backup car for practice on Thursday.

"It was understeer on the car, and even if I lifted the throttle on the entry of the corner, it was not enough, and I lost completely the front aero," said Alonso, the two-time Formula 1 champion and 2017 Indy 500 rookie of the year. "The wall came too close and too quickly. Unfortunately, it happened today.

"I'm sorry for the team, but we will learn and hopefully we will come back stronger tomorrow. I'm disappointed and sad for the team and for the guys. We worked quite a lot on the car and definitely now it's quite damaged, so I feel sorry for the team and for my mistake."

With just less than an hour remaining in practice, Rosenqvist made hard contact with the SAFER Barrier exiting Turn 2 in the No. 10 NTT DATA Chip Ganassi Racing Honda. Rosenqvist was also uninjured and team officials said he will move to a backup car as well.

"I was behind Colton (Herta) and just trying to run the car in traffic, and I just felt a very sudden change of having a bit of push, and it went very loose, very fast," Rosenqvist said. "I couldn't react to it.

"A shame, but that's how it is."

Indianapolis 500 practice resumes Thursday from 11 a.m.-6 p.m. ET, ahead of the "Fast Friday" practice at the same time. Both stream live on INDYCAR Pass on NBC Sports Gold.

Qualifying on Saturday runs from 11 a.m.-5:50 p.m. and will lock in the first 30 positions in the field. INDYCAR Pass will stream the first six hours, with NBCSN taking over from 5-6 p.m.

The second qualifying day on Sunday will determine the final three starters in the 33-car field in the Last Row Shootout, followed by the Fast Nine Shootout to decide the pole sitter and starting order of the first three rows. NBC has live coverage from noon-3 p.m.

The Indianapolis 500 airs for the first time on NBC on Sunday, May 26. Live coverage begins at 11 a.m.